I bought this to replace a smaller (Seagate 2.5") drive. I figured 3TB would last me for a while (I shoot a lot of large RAW images). The USB 3 specification was welcome because I could get the best performance using it with my MacBook Retina Display. I also liked the fact that there were adapters available to use the same drive with Thunderbolt. So much for specifications. This drive is painfully slow, another reviewer indicated that some of the devices ship with 5400rpm drives. I think I must be one of the unlucky ones. It slows down my machine, it is worse than the 2.5 it replaced. Now, to add insult to injury the 3.0 adapter no longer fits properly with the main body of the device meaning that the drive intermittently shuts off and I have to wiggle it to try to get contact and re-mount the drive. This 'wonderful' adapter technology is simply not ready for prime time. I just wish I could get my money back and will NOT be buying or advising any of the people who consult with me to buy this brand. Most irritated!
UPDATE: It appears that the problem is the USB 3.0 cable - at least with the drive disconnection. I tried a couple of other cables and those seemed to work okay. This is a deal breaker - bad cable makes the entire product fail.